Creep fatigue damage assessment method for superheater tube plate

A superheater tube, fatigue damage technology, applied in the direction of applying stable tension/pressure to test the strength of materials, etc., can solve the problem of not considering non-isothermal conditions or multi-holding creep behavior, unable to predict the history of creep stress relaxation, etc. , to achieve a strong intuitive effect

Active Publication Date: 2021-06-29
EAST CHINA UNIV OF SCI & TECH
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Problems solved by technology

[0004] However, since the linear matching-extended direct steady-state cyclic analysis method (LMM-eDSCA) can only consider the isothermal creep parameters in one load cycle and one dwell period, it does not consider non-isothermal conditions o

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  • Creep fatigue damage assessment method for superheater tube plate
  • Creep fatigue damage assessment method for superheater tube plate
  • Creep fatigue damage assessment method for superheater tube plate

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Embodiment Construction

[0088] Below, according to the drawings, preferred embodiments of the present invention are given and described in detail, so that the functions and features of the present invention can be better understood.

[0089] see figure 1 A creep fatigue damage assessment method for a superheater tube sheet disclosed in the present invention comprises the following steps:

[0090] S1: The steady-state cycle analysis method is modified by considering the three factors of non-isothermal creep, multiple loads and creep relaxation history during the load period.

[0091] Among them, S1 specifically includes:

[0092] S11: Establish a creep strain calculation equation including non-isothermal effects, and the creep strain calculation equation is:

[0093]

[0094] A=A * exp(-Q eng / R gas T) (2);

[0095] in, is creep strain rate, A, n, m are creep material constants, σ ​​is stress value, t is holding time, A * is the frequency factor, Q eng is the activation energy, R gas is ...

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Abstract

The invention provides a creep fatigue damage assessment method for a superheater tube plate. The creep fatigue damage assessment method comprises the steps of correcting a steady-state cyclic analysis method; combining a CAE model, a yield stress and temperature related ideal elastic-plastic model and a temperature related creep constitutive equation, and analyzing the creep cycle plasticity behavior of the tube plate in the steady-state cycle; designing a fatigue curve to evaluate fatigue damage by adopting a general slope method; evaluating creep damage by adopting a time fraction method, a ductility depletion model or a strain energy density depletion model; and evaluating the creep fatigue damage according to a linear damage superposition criterion or a unified creep fatigue equation. According to the creep fatigue damage assessment method for the superheater tube plate, the non-isothermal creep effect, the multiple load holding periods and the stress-strain relaxation history in the load holding periods are considered, creep fatigue total damage assessment can be conducted on the superheater tube plate, and the creep fatigue damage assessment method has the advantages of being visual, high in applicability and high in accuracy.

Description

technical field [0001] The invention relates to the field of creep fatigue damage assessment, in particular to a creep fatigue damage assessment method for superheater tube sheets. Background technique [0002] As a traditional standard shell-and-tube heat exchange equipment, superheaters are key components of steam power plants and are widely used in the petroleum and energy industries. As a typical single-phase heat exchanger, the steam flows in the inner tube and allows the external flue gas to heat the steam in a cross-flow (cross-flow or cross-flow). The production and maintenance of superheaters are relatively simple, inexpensive, and highly adaptable, able to withstand high temperature and high pressure working conditions. Among the many parts of the superheater, the tube sheet is one of the most critical parts attached to both the tube layer and the shell layer. In tube sheets subjected to thermal and mechanical loads, extremely complex loading conditions can often...

Claims

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Application Information

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IPC IPC(8): G01N3/08
CPCG01N3/08Y02E60/00
Inventor 王润梓孙佳锦李凯尚张显程涂善东
Owner EAST CHINA UNIV OF SCI & TECH
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